Moving window display system



March 19, 1963 J, c, DEAN 3,082,294

1 I MOVING WINDOW DISPLAY SYSTEM Filed May 10, 1960 5 Sheets-Sheet 1 2INPUT INPUT W050 sWvc sWvc GEM AND SWITCH 9/255. l 1 155.2 A B SYNC I90,/9b 0 A B ourpur 20 ourpur W050 W050 T SYNC W050 SWEEP /2/ GEM r 2a TEL5Ws 101v MON/TOR To 5 I DISTRIBUTION NET I L "IL 1 INVENTOR J CARROLLDEAN ATTORNEY March 19, 1963 Filed May 10, 1960 J. C. DEAN MOVING WINDOWDISPLAY SYSTEM TRIGGER FROM DA TA SYSTEM 3 Sheets-Sheet 2 TUBE A TUBE asY/vc I90 '-20 /9b 28 VIDEO SWITCH I SWEEP GEM 2/ I s FREEZE 26 GATE I23 L 30 5 29 L, i 3/ 33 a2 25 i 1 7 TELEVISION 22 I u \1 T0 q; MON/TOR 1E o/srmaur/m/ NETWORK l I J l I l H/ VOLTAGE SWITCH SWEEP GEM INVENTOR JCARROLL DEAN ATTORNEY United States This invention relates to videodisplay systems generally and more particularly to a moving windowdisplay system for presenting video information on a continuous stripbasis.

A moving window display is a display system that gives a viewer theimpression that he is looking through a window moving past some scene. Adisplay device of this type may be utilized to great advantage with datasystems which present video information on a continuous strip basis. Anydata system, regardless of other excellent characteristics, is limitedby its readout device. A moving window display system is of particularvalue when used as a readout device with some type of strip mappingequipment such as IR reconnaisance gear, sidelooking radar, or any othertype of equipment that takes information within some temporarily definedwidth and a temporarily undefined length.

In spite of the large dollar volume of strip mapping equipment presentlyin the. field, there are serious limitations in the associated displaysystems and readout devices now in existence. Previous strip-type videodisplays have often required dark adaptation and the display equipmentutilized has had pronounced phosphoric decay characteristics. Previoussystems have also experienced excessive presentation delay anddisturbing frame or flopover rates, and many of these systems are notable to present a complete picture at all times. Consequently, it isonly after considerable indoctrination and experience that a viewer canadequately interpret the display presented by these systems.

In order to alleviate some of the disadvantages which are inherent inexisting video display systems, some of the presently employed readoutdevices utilize a fast film processing technique. By this technique,data received from a data system is recorded on film, processed, andthen used. In general, these devices are cameras first and a displaysecond, and thus great expenditures of film are necessary to merelypresent a transient display. Also, in these photographic systems, thetraverse rate ratios of the presentation are limited and the accesstimes are large in proportion to the traverse rates.

A primary object of this invention is to provide a moving window displaysystem for the display of video information which will require a minimumof viewer conditioning, experience, or familiarity in order to obtainmaximum information with maximum speed and accuracy and minimum fatigue.

Another object of this invention is to provide a moving window displaysystem for the display of video information which will provide atransient display of transient data with no requirement of darkadaptation.

It is a further object of this invention to provide a moving windowdisplay system for the display of video information which has no visibleframe or flop-over rates and which always presents a complete picture tothe viewer.

Another object of this invention is to provide a moving window displaysystem for the display of video information which experiences no accessdelay and which has no reasonable limits on traverse presentation ratesor ratios.

A further object of this invention is to provide a moving window displaysystem for the display of video information which permits the freezingof a particular scene for concentrated examination.

attlt 'ice Another object of this invention is to provide a movingwindow display system for the display of video information which iscompletely electronic and includes no mechanical moving parts.

A further object of this invention is to provide a moving window displaysystem for the display of video information which permits multiplesimultaneous viewing of a video presentation via ordinary televisionremoting networks.

Another object of this invention is to provide a moving window displaysystem for the display of video information which utilizes a pluralityof television monitors to permit the simultaneous viewing of a transientdisplay of data and a frozen scene taken therefrom.

A further object of this invention is to provide a method for displayingvideo information from a data system as a continuous transient display.

Another object of this invention is to provide a method for displayingvideo information from a data system as a continuous transient displayutilizing a single storage tube.

A still further object of this invention is to provide a method fordisplaying video information from a data system as a continuoustransient display from which particular scenes may be frozen forconcentrated examination.

With the foregoing and other objects in view, the invention resides inthe following specification and append ed claims, certain embodimentsand details of construc tion of which are illustrated in theaccompanying drawings, in which:

FIGURE 1 is a block diagram of a two tube moving window display readoutdevice of the present invention;

FIGURE 2 shows a chart illustrating a switching sequence within thereadout device of the present invention;

FIGURE 3 shows a chart illustrating a switching sequence with erase timefor the readout device of the present invention;

FIGURE 4 discloses the moving window display device of the presentinvention in which means are provided to freeze a particular scene forprolonged examination; and

FEGURE 5 is a block diagram of a combination sweep generator andsynchronization generator with switch which may be used with the presentinvention.

Referring now to FIG. 1, the moving window display device of the presentinvention indicated generally at ltl comprises a synchronization pulsegenerator and switching unit 11 which receives input video signals froma data system 12 by means of a video input 13. The synchronization pulsegenerator and switching unit 11 also receives input synchronizationsignals from a synchronization signal source 14 by means of an inputlead 15'. The synchronization pulses from source 14 are timed inrelation to the input video signals from the data system 12 so that theinput video will be accepted by the synchronization generator andswitching unit 11. Synchronization pulse generator ll. provides videoplus synchronization pulses to the input sides 16a and 16b of two dualgun CRT storage tubes A and B, of which the Raytheon tube (215703 is anexample, and also to a sweep generator 17. The synchronization pulsegenerator and switching unit 11 also acts as a mode switch toalternately prime storage screens 18a and 13b of the storage tubes A andB to condition them for the reception of video material. Time constantsproportional to the rate at which the video sig nal is received from thedata system 12 are set within the synchronization pulse generator andswitching unit 11 to control the time period during which either thescreen 18:: or 1811 is energized.

The input sections 16a and 16b of the CRT storage tubes A and B includethe deflection plates or coils and write guns (not shown) which areusually provided in tubes of this type, while the output sections 19aand 19b of the storage tubes A and B include the normal deflectionplates or coils and readout'guns (not shown). The write guns in theinput sections 16a and 16b receive the video plus synchronizationsignals from the synchronization generator and switching unit 1 1,while'the deflection plates or coils in the input sections 16a and 16breceive horizontal and vertical sweep signals from the sweep generator17. The write guns transcribe the video signals upon the tube screens18:: and 13b in accordance with the sweep signals received from sweepgenerator 17; The read guns in output sections 1% and 19b sweep thescreens 18a and 18b and provide the read video output signal to acombined synchronization pulse generator and video switch 20. In returnthe read guns receive a synchronization signal from the synchronizationpulse generator and video switch 2%. Combined unit 26 receivessynchronization pulses from input synchronization pulse source 14 and inturn provides synchronization pulses to control a sweep generator 21which furnishes the sweep signals to the deflection plates in outputsections 19a and 1911, as well as to a television monitor 22.Synchronization signal generator and video switch 20 also provides videoand synchronization signals to the television monitor 22 and to adistribution network 23.

Although the synchronization pulse generator and video switch 2!receives the input synchronization pulses from source 14, as does thesynchronization pulse generator 11, generators 11 and 26 are e'ach'freerunning with respect to the other. The pulse generator 11 operates at arate governed by the associated data system 12 and in turn causes thewrite guns in the input sections of storage tubes A and B to transcribethe data line by line on the storage screens 13a and 18b of the storagetubes. The pulse generator 20 may operate at a much faster rate thandoes the pulse generator 11, thus causing the read guns in the outputsections of the storage tubes to scan the screens 18a and 1812 veryrapidly. The read scan may be so rapid that it appears that theinformation is being flashed on the screen instantaneously instead ofbeing written line by line. The synchronization pulses from source 14are fed to the generator 20 merely to insure that it is in operationwhen video information is being received by the storage tubes A and B.

The video switching section of the synchronization generator and videoswitch 2% acts in much the same manner as does the timed switch in thesynchronization generator and switching unit 11, and periodicallyswitches between the output sections of tubes A and B so that videoreadout signals are received in succession from the output section offirst one tube and then the other.

The operation of the readout device shown by FIGURE 1 requires that theinput video and the output video be switched sequentially from tube A totube B in order that a physical traverse movement may be produced. Thisswitching operation, which is controlled by the switching sections ofunits 11 and 20, in itself does not produce the traverse movementnecessary for a moving window display. In order to explain the basicoperation of the display device of FIGURE 1, only the input (write) andoutput (read) modes of the dual gun storage CRT tubes A and B will beinitially considered. If the moving window display device has been inoperation for some length of time, the input or write gun in inputsection 16a of storage tube A will have laid upon the storage screen 18aof this tube by a line-by-line scan, a raster A1, as shown graphicallyin FIGURE 2. The line scan rate and the traverse rate, which is the rateat which one line follows another, are both determined by the associateddata system 12. The output of the read gun in the output section 1% ofstorage tube A develops a read raster of the same physical size as theraster A1 developed by the write gun in input section 160, and theentire out- 4 i put raster moves down the storage screen at the traverserate of the input gun.

Referring to the switching sequence diagram of FIG-- URE 2, with theraster Al on the screen 18a of storage tube A, the output or read rasterstarts with its upper edge indexed on the upper edge of A1 and movesdownward. However, as the raster A1 of the write gun and the raster ofthe read gun are of the same physical size, as soon as the output movesdown one line, it no longer contains a complete rasterful of informationand thus A2 must be started as a continuation of A1. Simultaneous withthe writing of the first line of A2 by the write gun of the inputsection 16a, the first line of B2 must be written with the identicalinformation on the screen 18b by the write gun of input section lfib'oftube B. As the Writing of A2 is continued andtollowed by the A output orread raster, B1 is also written as evidenced by the diagram of FIGURE 2.Thus when A2 is complete and the A output raster has traversed to thebottom of A2, i.e., the bottom line of the output raster is indexed withthe bottom line of A2, a complete scene has become available on the Btube at raster B1 and the video presentation is now switched and takenfrom the B output gun. The cycle is then repeated by simultaneously andidentically writing the first line of B2 and a new A1, and the B outputraster, which is indexed on B1, then traverses down to enclose B2. Whenthe B output raster reaches the bottom of B2, switching again takesplace and the A output, indexed at A1, is sampled. Thus the A input gunlays a scene on the storage screen 18a. that is the same width but twiceas long as the A output or read raster. The A output raster moves downthe scene to its physical extremity and in the meantime the B input gunhas developed enough of its scene so that the B output raster can beturned on and moved over the B scene which is a continuation of the Ascene. This switching and reading procedure between tubes A and Bcontinues until the whole video scene from the data system 12 has beenpresented in one continuous sequence. This video scene is passed fromcombined unit 20 to a television monitor 22 and to a distribution system23. Distribution system 23 may incorporate a large number of auxiliarytelevision monitors so that the video scene can be viewed at numerouspoints.

In the description of the basic operation of the system of FIGURE 1 asgraphically illustrated by the diagrams of FIGURE 2 it will becomeapparent that no time has been allowed in which to accomplish theerasure of screens 18a and 1815. This time is made available by lettingthe input guns of tubes A and B write a -few more lines so that a rasteris produced which is slightly more than exactly twice the physical sizeof the output rasters. Thus during the time in which the B output isreading the extra lines at the bottom of B1, and A screen is beingerased and primed or conditioned. Then the A screen is prepared forwriting with the first lines of B2. This mode of operation is showngraphically in FIGURE 3 where sections marked X indicate graphically thetime in which the conditioning of each raster takes place. This timecould also be shown graphically at the bottom of A2 and B2, as it doesnot matter electrically where it occurs as long as suflicient extrareading time and information is provided. The sections marked X do notphysically appear on the storage screens 18a and 1812 but are merelyutilized to graphically illustrate the raster erasure period. It will benoted that the addition of extra information lines to the rasters of Aand B requires a proportionate increase in time for conditioning, butthis conditioning time is small compared to the traverse rate of thepresentation. The total conditioning time may be expressedmathematically as an asymptotically converging series, the approximatevalue of which can be increased by 50l00% with no loss in video outputduty cycle.

FIGURE 5 shows a block diagram of a typical synchronization generatorand switch combined with a sweep generator unit which might be utilizedin the circuit of FIGURE 1 as the synchronization generator and switch11 and the sweep generator E7, to provide the switching sequencedescribed in connection with FIGURES 2 and 3. In the system illustratedby FIGURE 5, synchronization pulses are furnished from thesynchronization pulse source 14 to a synchronization generator 36.Output pulses from synchronization generator 36 are in turn fed to thevertical sweep generator 37, a horizontal sweep generator 38, a pulsecounter 39, and an erase and prime sweep generator 5% The pulse counter3% acts as a timing unit, and after receiving a specified number ofpulses from the synchronization generator 36, it furnishes an outputpulse to a gate generator 4%. Gate generator so may include any suitablegenerator for producing a pulse output upon the reception of an inputpulse. Generator 49 controls the sweep signals which are sent to thestorage tubes A and B, and it also actuates two high voltage switches 43and 44 which control the potential upon the screens of the storage tubesA and B. The output from the gate generator 4! is sent to a verticalgate generator 51 and to a horizontal gate circuit 42, as well as to thetwo high voltage switches 4-3 and 44. The vertical gate generator 51 isconnected to two vertical gate circuits lla and 41]), the control inputto the vertical gate 41a from the vertical gate generator 51 is coupledto the high voltage switch 43, while the control input from the verticalgate generator 51 to the vertical gate 41b is coupled to the highvoltage switch 44. The vertical gate circuits 41a and llb also receivean input si nal from the erase and prime sweep generator 5% The verticalgates 41H and 41b and the horizontal gate 42 are each composed of anysuitable gating circuit which, upon the reception of a control signalfrom either the gate, generator 4t? or the vertical gate generator 51,will selectively pass an output signal to one or two output systems.Vertical gates 41:; and 41b selectively provide either a vertical sweepsignal from the vertical sweep generator 37, or an erase and primesignal from the erase and prime generator 5%, to a vertical sweepamplifier 45 for the A CRT storage tube or to a verticalsweep amplifier46 for the B CRT storage tube. The horizontal gate 42 selectivelyprovides a horizontal sweep signal from the horizontal sweep generator33 to a horizontal sweep amplifier 47 for the A CRT storage tube or to ahorizontal sweep amplifier 48 for the B CRT storage tube. The verticalsweep amplifier MS and the horizontal sweep amplifier 47 provide sweepsignals to the deflection plates or coils in the input section 16a ofthe dual gun storage tube A, while the vertical sweep amplifier 46 andthe horizontal sweep amplifier 48 provide sweep signals to thedeflection plates or coils in the input ection b of the dual gun storagetube B. High voltage switches 43 and i iare selectively controlled bythe pulses from the gate generator id so that a potential is furnishedto the screen of the CRT storage tube which is receiving the sweepsignals from the selected sweep amplifiers. The video signals from thedata system 12 are fed to a video amplifier 49, which amplifies them andthen directs them to the write guns in the input sections 16a and 16b ofthe CRT storage tubes A and B.

In the operation of the combined synchronization gen erator, switch, andsweep generator of FIGURE 5, synchronization pulses are received fromthe synchronization pulse source 14 and are fed to the synchronizationgenerator 6, which in turn directs them to the vertical sweep generator37, the horizontal sweep generator 38, the pulse counter 39, and theerase and prime sweep generator 50. Pulse counter 39 is set to providean output pulse after the duration of the period of time required toproduce a complete video scene upon the screen of either of the CRTstorage tubes A or B. The output pulse from the pulse counter s9 isdirected to the gate 6 generator '40, which in turn controls theswitching sequence of the horizontal gate 42 and the two high voltageswitches 43 and 44, and provides control pulses to the vertical gategenerator '51. Upon receipt of the control pulses from the gategenerator 49, the vertical gate generator 51 operates to provide controlpulses to the vertical gates 41a and 41b. The vertical gates 41a and 41breceive vertical sweep signals from the vertical sweep generator 37, andalso erase and prime signals from the erase and prime sweep generator50. 'The control signals from the vertical gate generator 51 cause thevertical gates 41a and 41b to selectively provide either an erase andprime signal from the erase and prime sweep generator St! or a verticalsweep signal from the vertical sweep generator 37 to the A verticalsweep amplifier 45 or to the B vertical sweep amplifier 46. Thus whenthe vertical sweep signal from the vertical sweep generator 37 is passedthrough the vertical gate 41b to the B vertical sweep amplifier i6 andthen to the deflection plates or coils in the input section of the B.CRT storage tube, an erase and prime signal is being passed from theerase and prime sweep generator through the vertical gate 41a to the Avertical sweep amplifier 45 and then to the deflection plates or coilsin the input section of the A CRT storage tube. Upon the reception of acontrol pulse by the gate generator '46 from the pulse counter 39, apulse is furnished to the vertical gate generator 51 to enable it toprovide a control pulse to the vertical gate circuits 41a and d-lbcausing a switching operation which permits the vertical sweep signalfrom the vertical sweep generator 37 to pass through the vertical gate41a, while the erase and prime sweep signal from the erase and primesweep generator 50 is now permitted to pass through the vertical gate411). The

' control signal from the vertical gate generator 51 is applied to thevertical gate 41b, the high voltage switch 44, the vertical gate 41a andthe high voltage switch .43, so that the high voltageswitches 43 and ldmay selectively provide erase, prime, or write potentials to the storagescreens of the A or B CRT storage tubes in accordance with the sweepsignals fed to the deflection plates or coils of the A and B CRT storagetubes from the vertical sweep amplifiers 45 or 46. It may therefore beseen that while vertical sweep signals are being furnished so thatinformation may be reproduced upon the screen of one of the CRT storagetubes A or B, the screen of the remaining tube is receiving erasesignals'from the erase and prime sweep generator 50. Upon the receptionof a synchronization pulse from the synchronization generator 36, theerase and prime generator 50 becomes free running and provides highfrequency sweep signals which, when fed to the deflection plates orcoils in the input section of either the A or B CRT storage tube, causethe input or write guns in this input section to write rapidly over thestorage screen of the tube to remove the information contained thereon.

Upon the reception of a control pulse from the gate generator ll thehorizontal gate 42 selectively sends a horizontal sweep signal from thehorizontal sweep generator 38 to either the horizontal sweep amplifier4-7 or the horizontal sweep amplifier 48. The horizontal sweepamplifiers 47 and 48 in turn send the horizontal sweep signals to thedeflection plates or coils in the input sections of either the A or 13CRT storage tubes.

Video data is continuously fed from the data system l2 through the videoamplifier i-9 to the input sections of storage tubes A and B, but thisdata cannot be reproduced upon the screen of either storage tube unlesssuch screen has been primed by a potential from the respective one ofthe high voltage switches 43 or 44. Thus the gate generator 4;}controls'both the switching sequence and the sweep signals so that thevideo scene is selectively reproduced in sequence upon the screens ofthe CRT storage tubes A and B.

7 In the moving window display system shown by FIG- URE 1, more dual gunstorage tubes may be employed if necessary in order to provide very fasttraverse rates. The number of storage tubes utilized will depend uponthe requirements of the associated data system 12.

In many instances it might become desirable to freeze the particularscene from the storage tubes A or B for prolonged examination. FIGURE 4discloses the use of an additional freezing storage tube C, which isnormally inactive, in conjunction with the moving window display systemof FIGURE 1. The addition of dual gun storage tube C permits theswitching sequence to be modified so that a tube containing the scene ofinterest can be removed from sequential operation. In the freeze systemillustrated by FIGURE 4, the combined synchronization generator andvideo switch 20 of FIGURE 1 has been divided into an independentsynchronization generator 20 and a video switch 24, for clarity ofillustration. However, the individual units 20 and 24 operate in thesame manner described in connection with the combined unit 20 ofFIGURE 1. The freeze sequence is instigated by means of a mode switchingunit which includes two position switches 25, 26, and 27. Switch 25 isprovided in the circuit between video switch 24 and the televisionmonitor 22, and removes television mointor 22 from its normal operatingconnection with video switch 24, and connects it to dual gun storagetube C. Switch 25 is coupled by suitable mechanical or electricallinkage to the switch 26 which is positioned in the circuit between thesweep generator 21 and television monitor 22, and to the switch 27 whichis provided in the circuit 28 which connects the synchronizationgenerator 20 to a freeze gate 29. Freeze gate 29 is also connected tothe output of video switch 24 by means of a lead 30. The freeze gate mayinclude any suitable timed gating circuit, many of which are known tothe art, which utilizes a timing unit such as a pulse counter or acharging condenser to cause the gate to pass a signal for apredetermined time before it again opens and blocks the signal.

The output video signal from freeze gate 29 is fed to the dual gunstorage tube C, which includes an input or write section 31, an outputor read section 32, and a screen 33. The input and output sections 31and 32 contain the usual read and write guns and deflection plates orcoils which are commonly employed in the CRT storage tubes known to theart. The read or output section of tube C is directly coupled to thetelevision monitor 22 when the switch 25 is in the freeze position.

When the switch 27 is closed, the output pulses from the synchronizationgenerator 20 are fed to the freeze gate 29 causing it to open and passvideo signals from the video switch 24 to the input section 31 of CRTstorage tube C. Pulses from synchronization generator 20 are also fed toahigh voltage switch 35 which controls the potential upon the screen 33of the tube C and to a sweep generator 34 which provides sweep signalstothe write section 31 and read section 32 of dual gun storage tube C.Sweep generator 34 also feeds sweep signals to the television monitor 22via switch 26.

In the operation of the freeze system shown by FIG- URE 4, the actuationof the switch 25 from the normal to the freeze position causes switch 27to close and switch 26 to move to the dotted line position in FIGURE 4.Thus, television monitor 22 is no longer connected to video switch 24 orto sweep generator 21, but is instead connected to the output 32 ofstorage tube C and also to the sweep generator 34, while the freeze gate29 is connected to the output of the synchronization generator 20. If,for example, the scene on storage tube A is the one to be studied, thevideo signal from the readout section 19a of the tube A is now fed tothe video switch 24 and then to the freeze gate 29 by means of the lead30 instead of to the television monitor 22 as described in connectionwith the operation of the circuit in FIGURE 1. The synchronizationpulses from the synchronization generator 20 cause the freeze gate 29 toopen long enough to pass a complete scene of video from the video switch24 to the input or write section 31 of the storage tube C. Thesynchronization pulses from the synchronization generator 20 alsoactuate the sweep generator 34 so that sweep signals are fed to thewrite section 31 and the read section 32 of storage tube C, as. well asto the television monitor 22. The write guns within input section #31 ofthe storage tube C write the video information upon screen 33, while theread guns in the output section 32 read the information from screen 33and pass it to the television monitor 22. In contrast to the CRT storagetubes A and B of FIGURE 1, the input and output sections of the storabetube C, as well as the television monitor 22, receive sweep signals froma single sweep generator 34. Thus the input or write gun of tube Coperates at TV rates in contrast to the inputs of tubes A and B whichoperate at rates set by the data system 12. At the present US. TV rates,the. frozen scene would be written upon the screen 33 of tube C inapproximately 4, second which is, for this purpose, practicallyinstantaneous. The output or read section 32 of tube C also operates atTV rates in the same manner as do the out put sections 1912 and 19b oftubes A and B.

After the complete scene from storage tube A has been reproduced uponthe screen of storage tube C, the previously mentioned countingmechanism within the freeze gate 29 causes the gate to close so that nomore video signals may be received from the output 19a of tube A. Thescene from tube A, which has been reproduced upon the screen 33 of tubeC, will now be maintained until the screen 33 is erased by a suitableDC. voltage. This erasure is accomplished by the high voltage switch 35which includes a two state electrical switching circuit of any suitableknown type. When the switch 27 is closed, the high voltage switch 35receives synchronization pulses from the synchronization generator 20which cause it to switch to a mode which prepares the screen 33 of CRTstorage tube C for the writing and reading operation. When switch 27 isopened, the synchronization pulses are removed from the high voltageswitch 35 causing it to switch to -a second mode to provide an erasingand priming potential to the screen 33 of the CRT storage tube C.

It should be noted that with the freeze system of FIGURE 4, one observercan study the frozen scene from the tube C on the television monitor 22which has been removed from the normal system, while another observercan continue to view the normal moving display upon additional monitorsin the distribution network 23. When the observation of the frozen sceneis completed and the system is returned to normal operation, a completedscene will be available on the screen of one of the remaining storagetubes. Although some of the data coming into the system is irretrievablylost when the scene is frozen if only one monitor is used, the effectupon the accuracy of the complete presentation will prove to be almostnegligible, as data is also lost during the observation due to the humanfix ations of the observer.

Though the freeze system shown in FIGURE 4 is the preferred way toperform the freeze operation, it is also possible to use a freeze methodwhich would work on the combined basis of substitution and time sharing.This system would also utilize three dual gun storage tubes A, B and C,but tube C in this system, instead of being a separate free tube, wouldperform in rotation with tubes A and B in the normal mode of operation.When the freeze mode is initiated, whichever of the three tubes A, B, orC, which is being read, would stop its vertical read traverse andcontinue to readout its field of view in that fixed position. The writeline of this tube would continue in its usual routine until the bottomof the screen is reached, at which time it will switch to the next tubein the normal manner. The system will now continue to write in the usualtw'o tube sequence with the frozen tube held out. When the freeze modeis terminated, the tube that had been frozen will return to the normalsequence at the next point of the write switching between tubes.Although this sequence of operation would be advantageous because allthree tubes would operate on a time sharing plan and have approximatelythe same electrical age in deterioration, extreme switching techniqueswould be required t accomplish the complete sequence of operation.

The characteristics of the data collection system will determine thenumber of storage tubes required. For the sake of simplicity, the movingwindow display system herein described has consisted of two tubes fornormal operation and three tubes for the normal plus freeze operation.It is possible, however, within the above philosophy to operate morethan the two or three tubes, or to utilize a sinzle CRT storage tube toperform the normal switch sequences as well as the freeze operation. Ifa single tube is utilized, the screen of this tube would be divided intosectors, each sector performing the function of one of the CRT storagetubes shown in the circuits of FIGURES l and 4. It is obvious that if asingle CRT tube is utilized for the moving window display system, aplurality of input and output guns will be required for the normal andfreeze operations, and the number of individual screen sectors providedwill be limited by the size nad capacity of the tube utilized. Thenumber or" individual screen sectors provided within the single tubewill determine the traverse rate at which the video information from thedata s ystem can be reproduced upon a screen sector of the storage tube.

It will be readily apparent to those skilled in the art that the presentinvention provides a novel and improved moving window display systemwhich is capable of presenting a transient display of video informationwith maximum speed and accuracy. The arrangement and types of componentsutilized within this invention may be subject to numerous modificationswell within the purview of this inventor who intends only to be limitedto a liberal interpretation of the specification and appended claims.

I claim:

1. A moving window display system for use as a readout unit for a datasystem comprising a plurality of dual gun CRT storage tubes, said tubesincluding a storage screen, an input section having means for writing acomplete scene of data upon said storage screen, and an o'u-tput sectionhaving means for reading the data from said storage screen, inputcontrol means connected to the input sections of said storage tubes,said input control means including a sweep generator to provide sweepsignals to the input sections of said storage tubes, a synchronizationgenerator for providing synchronization pulses to the input sections ofsaid storage tubes, a pulse generating means for providing a primingpotential, and a switching means to direct said priming potential to thescreens of said storage tubes and being timed to sequentially switchbetween said plural storage tubes whereby the priming potential isprovided to the screen of each individual CRT storage tube for theduration of time required for the input section to produce a completescene of data upon said storage screen, a source of inputsynchronization pulses connected to said input control means, means tosupply a video signal from the data system to said input control means,output control means connected to the output section of said CRT storagetubes and to said input synchronization pulse source and operating inconjunction with said input control means to cause the scenes from thescreens of said plural dual gun CRT storage tubes to be removed insequence, and a visual display means connected to receive saidsequential data scenes from said output control means, said outputcontrol means including a sweep generator for providing sweep signals tothe output sections of said dual gun CRT storage tubes and also to saidvisual display means, and a combined synchronization generator and videoswitch which provides synchronization pulses to the output sections ofsaid stor- 10 age tubes and also to said sweep generator and visualdisplay means, said synchronization generator and video switch receivingoutput video signals from the output sections of said sequentiallyoperated plural ORT storage tubes and-in turn directing said videosingals to said display means.

2. A moving window display system of claim 1 in which thesynchronization generator of said input control means providessynchronization pulses at a rate determined by said data system, whilethe synchronization generator of said output control means providessynchronization pulses at a rate greater than that determined by saiddata system whereby the read means in the output sections of said pluralCRT storage tubes operate more rapidly than do the writing means in theinput sections of said plural storage tubes.

3. A moving window display system of claim 1 in which said visualdisplay means includes a plurality of interconnected televisionmonitors.

4. A moving window display system for use as a readout unit for a datasystem comprising a plurality of CRT dual gun storage tubes, means tosupply a video signal from the data system ot said storage tubes toproduce a scene of data information thereon, means to direct outputsignals from said storage tubes to a visual display means, switchingmeans to cause the output signals from said plural storage tubes to beindividually supplied in sequence to said display means, and means todirect certain output signals from said plural storage tubes to anindividual freeze system, said freeze system including a freeze gateconnected to receive the output signals directed from said storagetubes, a normally inactive dual gun CRT storage tube to receive thescene of data to be frozen, said storage tube including a storagescreen, an input section having means for writing a complete scene ofdata upon said storage screen, and an output section having means forreading the data from said storage screen, said input section beingconnected to said freeze gate and said output section being connectableto said visual display means, and control means connected between saidfreeze gate and said normally inactive dual gun CRT storage tube, saidcontrol means furnishing control signals to the input section, outputsection and screen of said normally inactive CRT storage tube.

5. A moving window display system of claim 4 in which the freeze gateincludes a timed gating circuit which permits the passage of the outputsignals from said plural CRT storage tubes for a time equal to the timerequired for the writing means in the input section of the normallyinactive CRT storage tube to produce a complete scene of datainformation on the screen thereof.

6. A moving window display system for use in readout unit for a datasystem comprising a plurality of dual gun CRT storage tubes, said tubesincluding a storage screen, an input section having means for writing acomplete scene of'data upon said storage screen, and an output sectionhaving means for reading the data from said storage screen, inputcontrol means connected to the input section of said storage tubes, asource of input synchronization pulses connected to said input controlmeans, means to supply a video signal from the data system to said inputcontrol means, output control means connected to supply control signalsto the output sections of said plural storage tubes and to in turnreceive video signals from said output sections, said output controlmeans including an independent synchronization generator which receivessynchronization pulses from the synchronization pulse 'source, visualdisplay means including a plurality of television monitors connected tosaid output control means to receive video signals therefrom, anindependent freeze system connected to said output control means, andmeans to direct selected video signals from said output control meanscausing the scenes 11 from said plural dual gun CRT storage tubes to" beindividually supplied in sequence to said display means.

7. The moving window display system of claim 6, in which the individualfreeze system includes a freeze gate, a normally inactive dual gun CRTstorage tube including a storage screen, an input section having meansfor writing a complete scene of data upon said storage screen, and anoutput section having means for reading the data from said storagescreen, the input section of said storage tube being connected to saidfreeze gate, control means connected between said freeze gate and saidnormally inactive CRT storage tube, said control means furnishingcontrol signals to the storage screen and input and output sections ofsaid normally inactive CRT storage tube, and mode swtiching means toselectively connect said freeze gate to the output control means of saidplural dual gun CRT storage tubes while concurrently connecting theoutput section of said normally inactive CRT storage tube to said visualdisplay means.

8. A moving window display system of claim 7 in which said modeswitching means disconnects one of the plural television monitors ofsaid visual display means from said output control means andconcurrently connects said individual television monitor to the outputsection of said normally inactive CRT storage tube, said mode switchalso concurrently connecting said freeze gate to said output controlmeans whereby said freeze gate receives both video and synchronizationsignals therefrom.

9. The moving window display system of claim 8 in which the freeze gateincludes a timed gating circuit, said gating circuit being actuated uponthe reception of synchronization pulses from said output control meansto pass video signals from said output control means to the inputsection of said normally inactive dual gun CRT storage tube for a timeequal to the time required by the writing means within said inputsection to produce a complete scene of data information upon the screenof said normally inactive dual gun CRT storage tube.

10. The moving window display system of claim 8 in which the controlmeans connected between said freeze gate and normally inactive CRTstorage tube of the freeze system includes a high voltage switchconnected to the screen of said normally inactive CRT storage tube, anda sweep generator, said sweep generator receiving synchronization pulsesfrom the synchronization generator of said output control means andfurnishing sweep signals to the input and output sections of saidnormally inactive CRT storage tube and also to the television monitorconnected to the output section of said normally inactive CRT storagetube.

11. The moving window display system of claim l in which the sweepgenerator of said freeze system causes the input and output sections ofsaid normally inactive CRT storage tubes to both operate at a commonstandard television rate.

12. The moving window display system of claim 11 in which the freezegate includes a source of priming potential, said source of primingpotential being connected to said high voltage switch and beingcontrolled thereby.

to provide a priming potential to the screen of said normally inactiveCRT storage tube.

13. A moving window display system for use as a readout unit for a datasystem comprising a single CRT dual gun storage tube having a storagescreen divided into a freeze portion and a plurality of normally activestorage portions, an input section and an output section, said inputsection including means for writing a scene of data upon said normallyactive portions of said storage screen and freeze writing means forWriting a scene of data upon said freeze portion of the storage screen,said output section including means for reading data from said normallyactive storage screen portions and freeze reading means for reading datafrom said freeze portion of the storage screen, input means to supply avideo signal from the data system to the input "section of said storagetube, output means to direct a signal from the output section of saidstorage tube to a visual display means, switching means to cause saidwrite and read means in the storage tube to operate sequentially on theindividual normally active portions of said storage screen to obtain acontinuous moving presentation on said display means, and means toselectively direct certain output signals from the output section ofsaid storage tube to the freeze writing means in the input section ofsaid storage tube, means to cause said freeze writing means to provide acomplete scene of data upon the freeze portion of said storage screen,means to disconnect said freeze writing means from the output of saidstorage tube after a complete data scene has been provided on saidfreeze portion of the storage screen, means to cause said freeze readingmeans to read the data scene from the freeze portion of said storagescreen, and means to direct said data scene to a visual display device,whereby said scene is frozen for prolonged examination.

14. A moving window display system for use as a readout unit for a datasystem comprising; input means to supply electrical data signals from adata system, electrical signal storage means having an input sectionincluding means for transcribing an electrical signal upon said storagemeans, and an output section having means for reading the electricalsignal from said storage means, input control means connected betweenthe input section of said storage means and said input means, said inputcontrol means providing control pulses to said input section wherebysaid transcribing means is caused to transcribe, line by line at a givenscan and traverse rate, a complete raster of input data from said datasystem upon said storage means, output control means connected to theoutput section of said signal storage means, said output control meansoperating independently of said input control means to provide controlpulses to said output section, whereby said reading means is caused todevelop a read raster of a size equal to the raster developed by saidtranscribing means and, simultaneously with the operation of saidtranscribing means, to move said read raster, line by line, down saidstorage means at a traverse rate equal to that of said transcribingmeans while scanning at a scan rate greater than that of saidtranscribing means so as to continuously remove and supply a changingdata signal from said storage means to said output control means, andVisual display means connected to receive the data signals from saidoutput control means, said visual display means being synchronized bysaid output control means with the read means in the output section ofsaid signal storage means, whereby said changing output data signals arecaused to provide a moving presentation upon said visual display means.

15. A moving window display system for use as a readout unit for a datasystem comprising; data input means to supply electrical data signalsfrom a data sys tem, a plurality of dual gun CRT storage tubes, eachsaid tube including a storage screen, an input section having means fortranscribing a complete scene of data upon said storage screen, and anoutput section having means for reading the data from said storagescreen, input control means connected between the input sections of saidstorage tubes and said data input means, said input consaid outputcontrol means operating independently of 13 said input control means toprovide control pulses to said output section whereby said reading meansis caused to develop a read raster of a size equal to the rasterdeveloped by said transcribing means and, simultaneously with theoperation of said transcribing means, to move said read raster, line byline, down said storage screen at a traverse rate equal to that of saidtranscribing means while scanning at a scan rate greater than that ofsaid transcribing means so as to continuously remove and supply achanging data signal from said storage screen to said output controlmeans, and visual display means connected to receive the data signalsfrom said output control means, said visual display means beingsynchronized by said output control means with the read- ReferencesCited in the file of this patent UNITED STATES PATENTS 2,403,562 SmithJuly 9, 1946 2,406,266 Sziklai Aug. 20, 1946 2,943,141 Knight June 28,1960

1. A MOVING WINDOW DISPLAY SYSTEM FOR USE AS A READOUT UNIT FOR A DATASYSTEM COMPRISING A PLURALITY OF DUAL GUN CRT STORAGE TUBES, SAID TUBESINCLUDING A STORAGE SCREEN, AN INPUT SECTION HAVING MEANS FOR WRITING ACOMPLETE SCENE OF DATA UPON SAID STORAGE SCREEN, AND AN OUTPUT SECTIONHAVING MEANS FOR READING THE DATA FROM SAID STORAGE SCREEN, INPUTCONTROL MEANS CONNECTED TO THE INPUT SECTIONS OF SAID STORAGE TUBES,SAID INPUT CONTROL MEANS INCLUDING A SWEEP GENERATOR TO PROVIDE SWEEPSIGNALS TO THE INPUT SECTIONS OF SAID STORAGE TUBES, A SYNCHRONIZATIONGENERATOR FOR PROVIDING SYNCHRONIZATION PULSES TO THE INPUT SECTIONS OFSAID STORAGE TUBES, A PULSE GENERATING MEANS FOR PROVIDING A PRIMINGPOTENTIAL, AND A SWITCHING MEANS TO DIRECT SAID PRIMING POTENTIAL TO THESCREENS OF SAID STORAGE TUBES AND BEING TIMED TO SEQUENTIALLY SWITCHBETWEEN SAID PLURAL STORAGE TUBES WHEREBY THE PRIMING POTENTIAL ISPROVIDED TO THE SCREEN OF EACH INDIVIDUAL CRT STORAGE TUBE FOR THEDURATION OF TIME REQUIRED FOR THE INPUT SECTION TO PRODUCE A COMPLETESCENE OF DATA UPON SAID STORAGE SCREEN, A SOURCE OF INPUTSYNCHRONIZATION PULSES CONNECTED TO SAID INPUT CONTROL MEANS, MEANS TOSUPPLY A VIDEO SIGNAL FROM THE DATA SYSTEM TO SAID INPUT CONTROL MEANS,OUTPUT CONTROL MEANS CONNECTED TO THE OUTPUT SECTION OF SAID CRT STORAGETUBES AND TO SAID INPUT SYNCHRONIZATION PULSE SOURCE AND OPERATING INCONJUNCTION WITH SAID INPUT CONTROL MEANS TO CAUSE THE SCENES FROM THESCREENS OF SAID PLURAL DUAL GUN CRT STORAGE TUBES TO BE REMOVED INSEQUENCE, AND A VISUAL DISPLAY MEANS CONNECTED TO RECEIVE SAIDSEQUENTIAL DATA SCENES FROM SAID OUTPUT CONTROL MEANS, SAID OUTPUTCONTROL MEANS INCLUDING A SWEEP GENERATOR FOR PROVIDING SWEEP SIGNALS TOTHE OUTPUT SECTIONS OF SAID DUAL GUN CRT STORAGE TUBES AND ALSO TO SAIDVISUAL DISPLAY MEANS, AND A COMBINED SYNCHRONIZATION GENERATOR AND VIDEOSWITCH WHICH PROVIDES SYNCHRONIZATION PULSES TO THE OUTPUT SECTIONS OFSAID STORAGE TUBES AND ALSO TO SAID SWEEP GENERATOR AND VISUAL DISPLAYMEANS, SAID SYNCHRONIZATION GENERATOR AND VIDEO SWITCH RECEIVING OUTPUTVIDEO SIGNALS FROM THE OUTPUT SECTIONS OF SAID SEQUENTIALLY OPERATEDPLURAL CRT STORAGE TUBES AND IN TURN DIRECTING SAID VIDEO SIGNALS TOSAID DISPLAY MEANS.